DVD-RAM and HAL aka "I'm sorry I can't do that sanely Dave".

demianph · 07-01-2008, 10:12 AM

Got slack 12 installed (see my post in installation subgroup).

When I insert a DVD-RAM (with an udf filesystem on it) into the drive (brand new lite-on) and try to do anything performance sucks! It constantly mounts and un-mounts the media (this causes interruptions in the data transfer and other issues). If I am copying files one at a time from a terminal window I end up accidentally putting a file into the mount point instead of the mounted media then we get into mount point hell because it starts spawning new mount points. If I am copying files via konqueror it copies them into the media only (no screw ups with the mount points) but performance still sucks and I watch the transfers stall constantly.

I found the reason why this is happening.

bash-3.1# ps -aef|grep hal
82 2789 1 0 09:20 ? 00:00:00 /usr/sbin/hald --daemon=yes
root 2790 2789 0 09:20 ? 00:00:00 hald-runner
root 2796 2790 0 09:20 ? 00:00:00 hald-addon-input: Listening on /dev/input/event3 /dev/input/event2 /dev/input/event1
82 2802 2790 0 09:20 ? 00:00:00 hald-addon-acpi: listening on acpid socket /var/run/acpid.socket
root 2808 2790 0 09:20 ? 00:00:00 hald-addon-storage: polling /dev/sr0 (every 2 sec)

I can find no other explination other then the 2 second rescan is for some reason unmounting the udf media and re-mounting it. Konqueror works because it pays attention and waits for the media to re-mount before it continues the copy (the stall status).

Is there a way to fix this behavior? It constantly pops up the "what do you want to do" dialog in KDE and if I try to manually mount (uncomment in fstab) the stupid 2 second scan un-mounts it before I can do something useful.

T3slider · 07-01-2008, 10:25 AM

Is your user in the plugdev and cdrom (and audio and video) groups? Add them manually using the following command:

Code:

# gpasswd -a username groupname

You may also have to change the permissions on a few files:

Quote:

Originally Posted by CHANGES_AND_HINTS.TXT

If you have permission errors when attempting to burn a cdrom or dvd image,
such as the following:
/usr/bin/cdrecord: Operation not permitted. Cannot send SCSI cmd via ioctl
then cdrecord almost certainly needs root privileges to work correctly.
One potential solution is to make the cdrecord and cdrdao binaries suid root,
but this has possible security implications. The safest way to do that is
to make those binaries suid root, owned by a specific group, and executable
by only root and members of that group. For most people, the example below
will be sufficient (but adjust as desired depending on your specific needs):
chown root:cdrom /usr/bin/cdrecord /usr/bin/cdrdao
chmod 4750 /usr/bin/cdrecord /usr/bin/cdrdao
If you don't want all members of the 'cdrom' group to be able to execute the
two suid binaries, then create a special group (such as 'burning' which is
recommended by k3b), use it instead of 'cdrom' in the line above, and add
to it only the users you wish to have access to cdrecord and cdrdao.

demianph · 07-01-2008, 10:43 AM

The DVD-RAM I wrote via my above description can no longer be read by an AIX system I was attempting to transfer files to.

The udf file system is still there and the linux machine reads/sees all the files and properties says it's still udf. AIX mounts it as udf , but I get errors trying to read and do not see the files. Even files put on from the AIX box before the linux box touched it are no longer accessible.

Could the constant mounting/un-mounting have caused an issue?

demianph · 07-01-2008, 10:48 AM

Quote:

Originally Posted by T3slider

Is your user in the plugdev and cdrom (and audio and video) groups?

Yes. The user is in all the proper groups. I have also tried as root just to be sure.

I get no errors but I get the following in /var/adm/messages:

Quote:

Jun 30 17:33:53 demian-6687 kernel: UDF-fs INFO UDF 0.9.8.1 (2004/29/09) Mountin
g volume '0 - UDF486938B8', timestamp 2008/06/30 15:49 (1f10)
Jun 30 17:34:37 demian-6687 kernel: UDF-fs INFO UDF 0.9.8.1 (2004/29/09) Mountin
g volume '0 - UDF486938B8', timestamp 2008/06/30 15:49 (1f10)
Jun 30 17:35:54 demian-6687 kernel: UDF-fs INFO UDF 0.9.8.1 (2004/29/09) Mountin
g volume '0 - UDF486938B8', timestamp 2008/06/30 15:49 (1f10)

I will go ahead and create the burning group and add the users to it, but I thought that udf was a filesystem and didn't go through the cd buring apps.

demianph · 07-01-2008, 11:19 AM

If I kill the hal scan of my DVD-Multi drive I can mount it and I dont see the I/O stalling but I still can not read what has been written on other machine. I think I will have to create a new udf fs on the media and try again.

demianph · 07-01-2008, 11:31 AM

On top of all this. Killing the HAL scan of the SATA DVD drive has improved my FTP rate from the PATA drives. When the hal scan is running FTP transfers from the hard disks seem to be interrupted like the writes to DVD-RAM were. Killing the hal scan caused the system to be able to write to DVD-RAM faster and without stalling as well.